System and method for transmission with creeper mode selection

Abstract

A mechanical creeper mode selection system for a transmission of a work vehicle is provided, in which the transmission includes one or more range modes having one or more range mode shift mechanisms each driven by an electrohydraulic circuit. The system includes a creeper mode selection lever movable by an operator to select a creeper gear range. The system also includes a sensor that observes a position of the creeper mode selection lever and generates sensor signals based thereon. The system includes a controller that processes the sensor data to determine a movement of the creeper mode selection lever and outputs one or more control signals to the electrohydraulic circuit to position the one or more range mode shift mechanisms in a range neutral mode based on the movement of the creeper mode selection lever.

What is claimed is: 
     
       1. A mechanical creeper mode selection system for a transmission of a work vehicle, the transmission including one or more range modes having one or more range mode shift mechanisms each driven by an electrohydraulic circuit, the system comprising:
 a creeper mode selection lever movable by an operator to select a creeper gear range; 
 a sensor that observes a position of the creeper mode selection lever and generates sensor signals based thereon; and 
 a controller that processes the sensor data to determine a movement of the creeper mode selection lever and outputs one or more control signals to the electrohydraulic circuit to position the one or more range mode shift mechanisms in a range neutral mode based on the movement of the creeper mode selection lever. 
 
     
     
       2. The mechanical creeper mode selection system of  claim 1 , wherein the creeper gear range comprises a high creeper gear range, a low creeper gear range and a creeper neutral gear range, and the controller outputs the one or more control signals based on the movement of the creeper mode selection lever out of the creeper neutral gear range. 
     
     
       3. The mechanical creeper mode selection system of  claim 2 , wherein the controller receives a selection of a range mode from a source of input, determines a position of the creeper mode selection lever based on the sensor signals and outputs one or more control signals to the hydraulic circuit to position the one or more range mode shift mechanisms in the selected range mode based on the position of the creeper mode selection lever in the creeper neutral detent. 
     
     
       4. The mechanical creeper mode selection system of  claim 1 , wherein the creeper mode selection lever includes a magnet, and the sensor is responsive to the magnet to generate the sensor signals. 
     
     
       5. The mechanical creeper mode selection system of  claim 4 , wherein the creeper mode selection lever is movable within a gate defined in a housing, and the sensor is coupled to the housing. 
     
     
       6. The mechanical creeper mode selection system of  claim 5 , wherein the gate defines a high creeper range detent, a low creeper range detent and a creeper range neutral detent, and the sensor is coupled adjacent to the creeper range neutral detent to observe the position of the creeper mode selection lever relative to the creeper range neutral detent. 
     
     
       7. The mechanical creeper mode selection system of  claim 1 , further comprising a source of a speed of the work vehicle, wherein the controller outputs the one or more control signals based on the speed of the work vehicle. 
     
     
       8. The mechanical creeper mode selection system of  claim 1 , wherein the one or more range mode shift mechanisms comprise one or more synchronizers, and the controller outputs the one or more control signals to stop a flow of hydraulic fluid to the one or more synchronizers based on the movement of the creeper mode selection lever. 
     
     
       9. A method for selecting a mechanical creeper mode for a transmission of a work vehicle, the transmission including one or more range modes having one or more synchronizers driven by an electrohydraulic circuit, the method comprising:
 observing a position of a creeper mode selection lever with a sensor; 
 determining, with a processor, a movement of the creeper mode selection lever based on signals from the sensor; and 
 outputting, with the processor, one or more control signals to the electrohydraulic circuit to direct a flow of hydraulic fluid to position the one or more synchronizers in a range neutral mode based on the movement of the creeper mode selection lever. 
 
     
     
       10. The method of  claim 9 , wherein the creeper mode selection lever is movable within a gate defined in a housing, and the observing the movement of the creeper mode selection lever further comprises:
 observing the movement of the creeper mode selection lever relative to the housing with the sensor, the sensor coupled to the housing. 
 
     
     
       11. The method of  claim 10 , wherein the gate defines a high creeper range detent, a low creeper range detent and a creeper range neutral detent, and determining, with the processor, the movement further comprises:
 determining that the creeper mode selection lever is moving from the creeper range neutral detent. 
 
     
     
       12. The method  claim 9 , wherein the observing the position of the creeper mode selection lever further comprises:
 observing a magnetic field generated by a magnet coupled to the creeper mode selection lever with the sensor. 
 
     
     
       13. The method of  claim 9 , further comprising receiving a source of a speed of the work vehicle, and the outputting the one or more control signals is further based on the speed of the work vehicle. 
     
     
       14. The method of  claim 9 , further comprising:
 receiving a selection of a range mode from a source of input; 
 determining, with the processor, the position of the creeper mode selection lever based on the signals from the sensor; and 
 outputting, with the processor, one or more control signals to the electrohydraulic circuit to direct a flow of hydraulic fluid to position the one or more synchronizers in the selected range mode based on the position of the creeper mode selection lever. 
 
     
     
       15. A mechanical creeper mode selection system for a transmission of a work vehicle, the transmission including one or more range modes having one or more synchronizers driven by an electrohydraulic circuit, the system comprising:
 a creeper mode selection lever movable by an operator in a gate to select a creeper gear range, the gate including at least a high creeper detent, a low creeper detent and a creeper neutral detent; 
 a sensor coupled to the housing that observes a position of the creeper mode selection lever in the gate and generates sensor signals based thereon; and 
 a controller that processes the sensor data to determine a movement of the creeper mode selection lever in the gate and outputs one or more control signals to the electrohydraulic circuit to position the one or more synchronizers in a range neutral mode based on the movement of the creeper mode selection lever from the creeper neutral detent. 
 
     
     
       16. The creeper mode selection system of  claim 15 , wherein the creeper mode selection lever includes a magnet, and the sensor is responsive to the magnet to generate the sensor signals. 
     
     
       17. The creeper mode selection system of  claim 16 , wherein the gate is defined in a housing, and the sensor is coupled to the housing adjacent to the creeper neutral detent. 
     
     
       18. The creeper mode selection system of  claim 15 , further comprising a source of a speed of the work vehicle, wherein the controller outputs the one or more control signals based on the speed of the work vehicle. 
     
     
       19. The creeper mode selection system of  claim 15 , wherein the controller outputs the one or more control signals to stop a flow of hydraulic fluid to the one or more synchronizers based on the position of the creeper mode selection lever. 
     
     
       20. The creeper mode selection system of  claim 15 , wherein the controller determines a position of the creeper mode selection lever based on the sensor signals and outputs one or more control signals to the electrohydraulic circuit to position the one or more synchronizers in a previously selected range mode based on the position of the creeper mode selection lever in the creeper neutral detent.